class Usher(object):
    
    KERNEL = "KERNEL" 
    USER   = "USER"
    
    def __init__(self):
        self.__os_mode = Usher.KERNEL
               
    def is_on_kernel_mode(self):
        return self.__os_mode == Usher.KERNEL
    
    def is_on_user_mode(self):
        return self.__os_mode == Usher.USER
    
    def set_kernel_mode(self):
        self.__os_mode = Usher.KERNEL
    
    def set_user_mode(self):
        self.__os_mode = Usher.USER
    

    
    